The invention covers a wide range of fasteners, fastening systems, fastener assemblies and related areas. These represent improvements over prior art fasteners and fastener assemblies, etc.
In aspects of the invention discussed below, reference is made to material adapted to contract when activated.
The material adapted to contract when activated is preferably shape memory alloy wire. Shape memory alloys are known and are usually made predominantly or wholly of titanium and nickel. They may also include other material, such as aluminium, zinc and copper. A shape memory alloy is capable of adopting one shape below a predetermined transition temperature and changing to a second shape once its temperature exceeds the transition temperature. Conversely, when the shape memory alloy cools below the transition temperature, it is capable of adopting the first shape again. In connection with the various aspects of the present invention, the shape memory alloy contracts when heated in situ. Shape memory alloy wire currently available, such as that sold under the trade mark Nitinol, is capable of contracting by about 3% when activated by heating.
Activation of the material adapted to contract when activated is preferably achieved through electrical resistance heating, with a wire feed to the assembly. Activation of the shape memory alloy wire can be initiated from a central location, using the wiring system of, for example, an air craft or automobile. It is also within the scope of this invention that the activation is initiated by remote means, such as a hand held tool operating through the use of any suitable form of energy, including microwave, electric magnetic, sonic, infra-red, radio frequency and so on.
The scope of the invention in its various aspects is not necessarily limited to the use of shape memory alloy. Other material may also be useful. Also, while activation may take place through heating, other means of activation may be suitable and are within the scope of this invention.
The fasteners and fastening systems of the invention may be particularly suitable for use in connection with automobiles and to some extent the description below may focus on this application. However, it is to be understood that the scope of the invention is not limited to this application.
There is a marked trend towards increasing electronic control in motor vehicles. Nowadays, many motor vehicles incorporate computer systems which use a Controller Area Network (CAN) in which modules communicate data to the computer via a bus, or a local interconnect network (LIN) which also enables communication of data via a bus.
The present invention in some of its many aspects is intended to take advantage of the trend towards increased electronic control in vehicles. The present invention provides several versions of fasteners which may be suitable for use in vehicles and which may provide significant advantages in relation to assembly of vehicles and service of vehicles. In particular, the fasteners of the present invention may be suitable for connection to a vehicle computer via a CAN or LIN.
Some fasteners and fastening systems of the invention can be designed to be activated only by authorised parties, such as those engaged in vehicle assembly or servicing. Others can be designed to be operated by vehicle owners.
In appropriate forms, any of the fasteners and the fastening systems of the invention can have primary and secondary functions, the primary function being to attach components to the vehicle body and the secondary function being the control of component switching. It is possible that use of fastening systems according to the invention may reduce the number of sub-network wiring components required in a vehicle, through direct connection into the CAN bus, for example. In effect, each fastener may become its own multiplex module/communications gateway or node on the CAN bus.